1. An extended scalar sector to address the tension between a fourth generation and Higgs searches at the LHC Xiao-Gang He, German Valencia, arXiv: 1108.0222 Koji TSUMURA (NTU) B3SM 23-25/10/2011 on behalf of X.-G. He

2. Koji Tsumura (ntu) 3 rd b3sm 2 Outline  Higgs boson in SM3 and in SM4 (Review)  gg  h cross section, Higgs decay  LHC result  (Electroweak constraint)  SM4 to SM4S  An extended scalar sector  Tension between SM4 and extra scalar  Summary He, Valencia, arXiv:1108.0222

3. Koji Tsumura (ntu) 3 rd b3sm  Gluon fusion mechanism  largest cross section!! Gluon fusion in SM3 3 Gluon Fusion gg  h even at 1-loop Sum over quark flavor

4. Koji Tsumura (ntu) 3 rd b3sm  Gluon fusion mechanism Gluon fusion in SM3 4 Sum over quark flavor top bottom

5. Koji Tsumura (ntu) 3 rd b3sm  Gluon fusion mechanism Gluon fusion in SM4 (sequential 4 th generation) 5 top Enhance factor 9 Sum over t and t’, b’

6. Koji Tsumura (ntu) 3 rd b3sm 6 Higgs decay in SM3 Main decay modes for heavy Higgs Z  4l can determine mass of Higgs Only 0.3%, but less BG events This can determine mass of light Higgs B(gg) is less than 10%

7. Koji Tsumura (ntu) 3 rd b3sm 7 Higgs decay in SM4 Main decay modes for heavy Higgs Z  4l can determine mass of Higgs Basically same as in SM3 B(gg) can be dominant in low mH region !! (40%) t’,b’

8. Koji Tsumura (ntu) 3 rd b3sm Main decay modes for heavy Higgs Z  4l can determine mass of Higgs Basically same as in SM3 8 Higgs decay in SM4 Reduce to 0.03% from 0.3%. Enhance tot. width, cancellation in .

9. Koji Tsumura (ntu) 3 rd b3sm  The results given @ LP2011  Roughly speaking, mH=140-450GeV is excluded !! 9 Present status of Higgs boson search in SM3 ~140GeV ~220GeV ~300GeV ~460GeV

10. Koji Tsumura (ntu) 3 rd b3sm  The results given @ LP2011 (in separate modes) 10 Present status of Higgs boson search in SM3  SM4 120GeV 600GeV

11. Koji Tsumura (ntu) 3 rd b3sm Gluon fusion revisited  Factor of 9? For low mass Higgs boson, top and t’, b’ give constant contributions. For high mass Higgs boson, top gives imaginary contribution and t’, b’ give real constant contributions.

12. Koji Tsumura (ntu) 3 rd b3sm  The results given @ LP2011  In SM4, mH=119-593GeV is excluded !! 12 Present status of Higgs boson search in SM4

13. Koji Tsumura (ntu) 3 rd b3sm What do we learn from Review?  Tension @ one-loop level. 13 SM4+X He, Valencia, arXiv:1108.0222

14. Koji Tsumura (ntu) 3 rd b3sm SM4 to SM4S (Smart?, Survive?, Simple?, Scalar?)  New colored scalar  QCD production: Testable new scalar @ LHC  Color triplet scalar (  squarks); skip in this talk  Color octet scalar [SU(2) doublet]  Rich flavor pheno. due to Yukawa int.  New physics model  loop induced neutrino mass 14 Color octet 4S4 He, Valencia, arXiv:1108.0222 Manohar, Wise, PRD74,035009(2006) Perez, Wise, PRD80, 053006(2009) Gresham, Wise, PRD76,075003(2007)

15. Koji Tsumura (ntu) 3 rd b3sm Exp. bound on octet  Flavor data  K   e, Bs  Xs ,   e   [Minimal flavor violation] or [ small Yukawa coupling]  Gluon fusion, and pair production 15 Gresham, Wise, PRD76,075003(2007) Manohar, Wise, PRD74,035009(2006) Gluon fusion (for Yt=1), No constraint for small Yukawa. S S S* Pair production, complicated final states (not yet constrained)

16. Koji Tsumura (ntu) 3 rd b3sm Scalar potential in SM4S  Scalar potential  Scalar Mass and Higgs coupling 16 2=2 3 (Custodial) Manohar, Wise, PRD74,035009(2006)

17. Koji Tsumura (ntu) 3 rd b3sm Tension between SM4 and extra scalar  Effective Lagrangian 17 He, Valencia, arXiv:1108.0222 Sum of S R, S I, S + contributions. Over all sign can be flipped by couplings Loop functions S

18. Koji Tsumura (ntu) 3 rd b3sm Gluon fusion in SM4S  Tension between SM4 and extra scalar  Clearly, scalar contributions can be destructive!!  How big?  For 1=-8, mS~2v, the first term ~ -1 (comparable to one 4G quark) M ~ 1(top) +2(t’,b’) -1(colored scalar) +(…)  You may add more “exotic” colored scalars. 18 Can be negative He, Valencia, arXiv:1108.0222

19. Koji Tsumura (ntu) 3 rd b3sm 19 Summary  Higgs boson in SM3 and in SM4 (Review)  gg  h cross section, Higgs decay  LHC result  (Electroweak constraint)  SM4 to SM4S  An extended scalar sector  Tension between SM4 and extra scalar Back to SM3 SM3 (SM4S 2 ?) SM4 He, Valencia, arXiv:1108.0222

20. Koji Tsumura (ntu) 3 rd b3sm  Electroweak constraint  Small splitting with mt’>mb’ Backup 20 Kribs, Plehn, Spannowsky, Tait, PRD76,075016(2007)